Electrical measuring system



June 6, 1950 c. A. vossBERG ELECTRICAL KEASURING SYSTEN `Filled NOV. 8,1945 4 Sheets-Sheet l VEN TOR.

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June 6 1950 c. A. vossBERG 2,510,485

ELECTRICAL msunmc sYs'rEn Filed Nov. 8. 1945 4 Sheets-Sheet 3 June 61950 c. A. vossBERG 2,510,485

ELECTRICAL IESURING SYSTE Filed Nov. 8, 1945 4 Sheets-Sheet 4 FIG.8

Patented June 6, 1950 ELECTRICAL MEASUBING SYSTEM Carl A. Vossberg,Lnbrook, N. Y., assignor to Standard Electronic Research Corporation,

New York, N. Y.

Application November 8, 1945, Serial No. 627,476

Claims. (Cl. 177-337) This invention relates to electronic measuringdevices and more particularly to an apparatus adapted for counting,metering, or computing.

One of the objects of this invention is to provide a high speed counterhaving a high degree of accuracy and versatility, and providing a visualindication of the actual number or other result of the measurement.

Another object of the invention is to provide such a device capable ofcounting a series of applied numbers, values or impulses, and beingcapable of adding further numbers, values, or impulses thereto so that anal count may be derived. Thus, the function of an electronic addingmachine or like apparatus may be served.

Anothr object of this invention is to provide a device for measuring thefrequency of a wave of energy, or the interval between two or moresucfor measuring accurately and precisely voltage,

and in fact any form of intelligence which can be converted intoelectrical pulses or which can be arranged to charge or discharge acapacitor or the like to a degree commensurate with the subject beingmeasured. The invention further provides a device for measuring thephase relationship between two wave motions, one of which may be anelectrical oscillation, while the other may embody a cyclical variationwhether electrical, mechanical, or both.

A further object of this invention is to provide an electrical countingdevice which can be interconnected with other counters as in a. cascadedarrangement, so as to perform the duties of a larger counter.

Another object of this invention is to provide a compact and largelyautomatic apparatus for receiving counts at extremely high speeds andthereafter providing an accurate visual indication of the quantity orcharacter of the received counts. Allied with this object is theprovision of such an apparatus capable of addition, subtraction, andinherently capable of performing the usual mathematical functions ofcomputing machines. The visual indicating means of the device is furtherarranged to occupy a small area. is simple in mechanical construction,and is of For the purposes of illustration, the description Y of theinvention herein will be principally directed toward its use as a.frequency measuring system although other applications will be describedor will be understood by those skilled in the art.

Referring to the drawings, Fig. 1 is a schematic circuit and blockdiagram illustrating two connecting or cascaded channels, in the systemherein described, similar channels being utilized for each digit orcharacter in the counted result.

Fig. 2 is a graphical illustration of the activity of each counterchannel during either idle or indicating periods when counts are notbeing applied thereto.

Fig. 3 is a similar view indicating a complete cycle wherein indicatingor synchronizing pulses are withheld from the divider.

Fig. 4 is a similar view indicating the application to the divider of asingle pulse to be counted.

Fig. 5 is a similar view illustrating the application of two pulses tobe counted by the apparatus herein.

Fig. 6 is a similar view illustrating the addi- Sion gf 3 pulses orcounts to the result obtained in i g.

Fig. 7 is a block diagram illustrating a complete counting apparatus andshowing the interconnection of the several cascaded channels.

Fig. 8 is a schematic circuit diagram illustrating a control apparatusfor actuating the counting or indicating channels.

Referring now to Fig. 7 of the drawings, I5 represents a highly stablefrequency source which, for purposes of convenience, is shown asproviding a. wave having a frequency of 100 cycles and which is used forsynchronizing the indicating system as hereinafter set forth. Means ofattaining such a reference frequency is apparent, one preferred methodcomprising stepping down the frequency from a crystal oscillator bymeans of multivibrators. However,

a tuning fork, a magnetostriction type of oscillator, or any otherfrequency generator or oscillator may be employed.

Control pulses, the function of which will be hereinafter described, andwhich are particularly a clarity whereby the results of the machines uuseful in frequency measuring, are obtained through frequency divider lEwhich may take the form of a. l cycle mutivibrator controlled byfrequency source l5. The output of divider I6 is amplilied at il so asto provide driving power for synchronous motor i8. The shaft I9 o motoril bears the count indicating or indicia bear-im; wheels 2D, 2l, 22 and23, which may be keyed thereto for uniform rotation. Although four suchindicating wheels are illustrated, 1t will be apparent that a completecounter may embody seven or more such wheels so as to have a countingcapacity of a million or more. However, it will be understood that thefunction for which the device is utilized will determine the desiredcapacity. Each wheel is numbered from zero to nine along its peripherywhen the device is employed as a measuring system'. In otherapplications the wheels may bear any suitable type of indicia such asletters or symbols if applicable.

Each count indicating wheel isV provided with its own channel fordetermining the particular number of that wheel to be rendered visibleor apparent so as to translate the intelligence applied to it, Each suchchannel is dual in form having two sections so as to permit the countsor pulses to be selectively absorbed or applied to the indicatingsystem. In this manner the apparatus is continuously functioning toeither receive counts or to indicate the result, the selection beingaccomplished by actuating either section of each dual :channel ashereinafter described. Each scale-of-ten divider is common to bothchannel sections so as to be incorporated in their circuits. Thus onechannel section comprises an indicating gate and divider while the otherchannel section comprises a signal gate and divider.

Each indicia bearing wheel is associated with neon tubes 24, 58 and 89and I9, which are adapted to render a particular portion of the wheelvisible through strohoscopic action. Since the wheels are rotated by thesynchronous motor I8 at 600 R. P. M., each wheel makes one revolutionevery one tenth of a second. If a neon tube,

Awhich supplies short flashes of illumination, is

ilashed once for every revolution of the disk, and in synchronismtherewith, only one number or other indicia appearing on the wheel willbe illuminated so as to be observed by the operator. In a normal periodprior to the application of .counts to the apparatus, the neon tubes maybe adapted to :dash so as to illuminate the zeros on the countingWheels, assuming that they are numbered :from zero to nine around theirperipheries. In this condition it may be considered that the neon tubeactuating circuit is in phase with the cyclical rotation ofthe countingwheels 20 to 23 as well as in synchronism therewith. As long as thesecircuits are thus in phase, the number zero will alwaysV appear on thewheels. In the event this phase relationship is caused to vary by theapplication of the subject to be measured, a diierent number will berendered visible upon any wheel in which this phase change has beenaccomplished. It will also be understood that subsequent to a changedphase relationship by the introduction of a. value to be measured, thesynchronous motor I8 maintains the wheels in synchronism with the neontubes, so that the new number or symbol rendered apparent on any wheelremains thus Visible until further4 counts are added or until a resetdevice restores the original phase relationship of each neon tube andwheel so that zeros once more appear thereon.

In the preferred embodiment illustrated herein each neon tube isactuated by charge of a, capacitor after gradual discharge thereofaccording to the value of the receivedcounts. At the instant that thecapacitor is recharged, as will be hereinafter described, a pulse isdelivered to the neon tube so as to dash it. The application of tencounts or equivalent voltage to the fully charged capacitor is arrangedto `elect a discharge thereof whereupon the circuit completely rechargesthe capacitor so as to produce a flash of the neon tube. Since' the neon'tube circuit and the rotating 'wheel arrangement are actuated from acommon source, and by virtue of the scale of ten divider abovedescribed, it may be considered that the neon tubes circuit and therotating wheels are of the same frequency in operation.

The principles embodied in this invention are graphically illustrated inthe time developed views of Figs. 2 to 6. The short vertical lines onthe top horizontal axis represent synchronizing pulses of energy assupplied from the cycle source l5 to section A o the counting channel'while the numbers represent those of the rotating wheels in theircyclical operation. The stepped arrangement shown in the guresillustrates the discharge of a capacitor which is effected by means ofthese pulses of energy. Thus, assuming that the capacitor is fullycharged at the zero point of the wheel as illustrated in Fig. 2,

each successive pulse serves to discharge the capacitor progressively,so that at the end of ten such pulses the capacitor is fully dischargedand, by the action of its circuit, is caused to recharge immediately atthe very time that the zero has again appeared.. Since the moment ofcapacitor recharge is simultaneous with the appearance of the zero onthe wheel, the zero will be rendered visible or apparent to theexclusion of the other figures through stroboscopic action. Reierringfurther to Fig. 2, it will be noted that the succeeding pulses likewiseaccomplish the discharge of the recharged capacitor and the zero iscaused to re-appear after the succeeding ten pulses. It will beunderstood that this action should have a repetition rate of about tentimes per second or more to take advantage of visual persistence, butless will be also practical.

If during the time of a complete cycle of ten pulses, the application ofthese pulses were to be removed from the capacitor circuit, then theirrestoration following the blanked-out period would nevertheless restorethe recharge time at the zero point. This would hold true only if thecondenser charge had not varied during the blanking period. The circuitto be described herein accomplishes this purpose and thus maintalus thecapacitor in a iixed state of charge by providing substantially nodischarge path therefor other than that controlled by the subject to bemeasured. In Fig. 3 is illustrated a period wherein no discharge pulsesare applied to the capacitor so that the resumption of application ofthese discharge or synchronizing pulses after an integral number ofrevolutions or tens of pulses maintains the indications at the zeropoint. As shown, the ten pulses which were omitted, start at .the timewhen numeral l would have appeared and the synchronizing or dischargepulses were applied once more when the numeral 1 again appeared. Thisblanking period olers a means to alter the indicated counts although.

as will hereinafter appear, the counts may be applied as well, duringthe period when pulses are discharging the capacitor. However,considering the blanking period as illustrated in Fig. 3, if onedischarge pulse originating from the subject to be counted instead offrom the source l5 is applied to the capacitor, the discharge thereofwould be accelerated to an extent depending upon the value of thisinserted pulse. The value of such subject pulses are arranged to beequal to the synchronizing pulses. Accordingly, when the synchronizingpulses in quantities of ten are restored to their discharging function,the capacitor will become fully discharged at the 9" point asillustrated in Fig. 4. It will, therefore, be apparent that the insertedpulse has changed the phase relationship between the numbered wheel asdeveloped along the top horizontal axis of Figs. 2 to 6, and thecapacitor discharge cycle. While the numerals are illustrated asprogressing from to 9, the wheels will be rotated oppositely, that isfrom 9 to 0 so that one discharge pulse from the external source wouldproduce the numeral 1 upon the capacitor recharge.

In Fig. 5 is illustrated a condition wherein two discharge pulses areapplied to the capacitor during the blanking period. Thereafter, whenthe synchronizing pulses are applied, the capacitor will recharge at the8 point of the wheel so that .the numeral 8 will become visible and willappear regularly thereafter as the synchronizing pulses are appliedthereto in complete cycles.

In Fig. 6 is illustrated a condition wherein three discharge pulses fromthe external source, or subject to be counted or measured, are added tothe two discharge pulses which were formerly applied as shown in Fig. 5.As illustrated therein, the recharge of the capacitor had occurred atthe numeral 8. The three discharge pulses added thereto discharged thecapacitor com-V mensurately so that the re-application of thesynchronizing pulses caused the recharge of the condenser after onlyfive such synchronizing pulses were applied. Thus, the numeral 5appeared on the wheel and reappeared continuously thereafter ascompleted cycles of synchronizing pulses were applied.

It will be observed that since the time of recharge of thecapacitorrrelative to the rotating wheel determines the count that isindicated, any means of displacing the cyclical discharge wave withrespect to the numbered wheel will render a different numeral visible.

The circuit illustrated in Fig. 1 is operative to effect suchaccelerated or phase displaced discharge of the capacitor. o Thesynchronizing pulses are applied from the 100 cycle source l5 to path orchannel section A through the capacitor 25, to the grid 26 of tube 21.Tube 21 is ordinarily maintained slightly beyond cut-olf as by battery28, although any source of bias may be employed. When positive pulsesfrom the 100 cycle source I5 are fed to the grid 26, the normal fixedbias will be overcome so as to produce output pulses at the plate oftube 21. As will be hereinafter explained, indicating gate tube 21,which is the input tube of the synchronizing pulse channel section A, isselectively operative with the input tube 23 of the subject receivingpath or channel B. Gate control means are provided to activate either ofthese tubes by removing or applying a further disabling bias therefromselectively. Assuming now that indicating gate tube 21 is in itsoriginal, operative state in parallel, although a single tube or twotriodes Y in a single envelope may be employed. Tubes 32 and 33 aremaintained beyond cut-off by battery 34. The function of these tubes isto apply discharge pulses through the cathodes 35 and 36 to thecapacitor 31 so as to discharge the same v in the manner shown in Figs.2 to 6. In actual practice, the batteries herein may be supplanted by asingle voltage source having suitable taps therein. Battery 34 isapplied through the Z connection shown.

Capacitor 31 is included in a multivibrator circuit comprising tubes 38and 39 which form a two stage amplifier with the output of one coupledto the input of the other. This sets up a condition for oscillation, butcapacitor 31 can only be charged in one direction which blocks tube 38.It will be observed that whereas conventional multivibrator circuitsinclude a grid leak resistance forming a time constant with the gridcapacitor and determining thereby the frequency of oscillation, themultivibrator circuit shown incorporates no such grid leak or dischargepath so that capacitor 31 maintains tube 38 disabled indefinitely untilmeans are provided to discharge or neutralize the charge on capacitor31. It will be appreciated that such discharge of capacitor 31 willpermit the multivibrator to oscillate once so as to immediately rechargethe capacitor and again block the tube. The parameters of the circuitare adjusted so that ten pulses from either tube 32 or 33 are requiredto discharge the fully charged capacitor 31 so as to produce one pulseof oscillation. Hence, for every ten pulses applied to the indicatingchannel described, one is transmitted thereby. Improvement in stabilityand greater freedom from effects due to parameter variations can besecured by increasing the supply voltage for tubes 32 and 33 and placinga limiting resistor in series with their grids. The plate load resistorscan be made very much greater than the tube resistance and the resultantcurrent will accordingly be substantially independent of tube constantswhen in the conducting state.

The transmission of one pulse bythe oscillation of the multivibratorcomprising tubes 38 and 39, flashes neon tube 2l which is included inthe plate circuit of tube 38 in place of the usual plate resistor. Thus,every ten pulses from the cycle source I5 will cause the neon tubeassociated with that particular channel to flash, unless a pulse orvoltage from another source is applied to the capacitor 31 to accelerateits discharge and cause the neon tube to flash before a full ten pulseshave been applied thereto from source l5. It will be recognized thatother gas or similarly functioning light flashing tubes may be employed.

Means for introducing such other excitation derived from the subject tobe measured is provided in path or channel section B of the dual channelarrangement for each rotating wheel. The introduced intelligence, inthis case an un- A of said gate control means.

7 known frequency, is applied a voltage as fx through amplifler 40 topulse Shaper 4|. The term "intel1igence refers of course to the intro-.duced signal or subject to be measured whether it is a wave ofparticular frequency, a number in the form of electrical energy, or anyother voltage to be analyzed since any subject to be measured takes theform of a voltage in the apparatus. The function of pulse Shaper 4| isto coordinate the value of the introduced pulses with that of thesynchronizing pulses. Otherwise stated, the

introduced pulses or other input voltage should have the same effect onthe discharge decrement as that of a normal synchronizing pulse. Theoutput of pulses shaper 4| is applied through capacitor 42 to the grid43 of tube 29 which functions as the signal gate. The output of tube 29is vapplied to phase inverter tube 44 through the coupling capacitor 45.Tube 29 is maintained beyond its cut-oif point by battery 48 which maybe the same voltage source as battery 28. As will hereinafter appear,tube 29 is controlled through auxiliary means so as to be considerablybelow cut-olf so that input pulses from the subject to be measured areof insufiicient amplitude to permit tube conduction except through theagency Assuming, however, that tube 29 is not thus disabled, andreceiving section B of the counting Wheel channel is operative, outputpulses from the plateof tube 44 will vbe applied through couplingcapacitor 46 to the grid 41 of the tube 33. Since tube 32 and 33 aresubstantially in parallel, the output of tube 33 in response to theexcitation from section B will be applied to capacitor 31 as a dischargedecrement in like manner as the synchronizing pulses from tube 32. Itmay be seen, therefore, that any pulses or other voltages introducedthrough section B will cause an acceleration of subsequent discharge ofcapacitor 31 so as to produce the correspondingly accelerated ash of theneon tube 24 in respect to the rotating indicia bearing wheel 20. Thus,the action hereinabove outlined for changing the phase relationshipbetween the numbered wheel and the capacitor discharge cycle inaccordance with the value oi the introduced intelligence, is accomlplished.

The apparatus herein described has two stable conditions during itsoperation. These conditions are first the absorbing or receiving .ofcounts through section B, and thereafter the indication of those countsthrough section A. Control means for activating either of these sectionsare provided by gate control 80 comprising the control tubes 49, and 5|,as illustrated in Fig. 8. Tubes 49 and 50 comprise a flip-flop type oftrigger circuit wherein either one, but not both, of these tubes can beconducting at any one time. Normally tube 50 is conducting and tube 49is in a non-conducting state byl virtue of the screengrid bias developedacross resistor 52 when tube 5| is red or when operate switch 53 isclosed. The usual grid current limiting resistors 49a are provided whilebattery 49h provides the proper bias through grid resistors 49e. Battery15 serves as the B voltage supply for tubes 49 and 59, and battery 16 isthe B supply for tube 5|. Resistors 11 and 18 are voltage droppingresistors to secure proper bias in tube 5|. Tubes 49, 50 and 5| areillustrated as being gas tubes of the Thyratron type, although ordinaryvacuum tubes may be used. Inasmuch as tube 49 is normally in thenon-conducting state, positive pulses from divider or multivibrator I5applied through capacitor 54 can not fire this tube unless thescreen-grid bias is removed. Due to the normal condition of the nip-flopcircuit and since tube 50 is conducting, voltage is developed acrosscathode load resistor 55 at point Y instead of across cathode loadresistor 56 at point X. Since the point Y is connected to the cathode 51of tube 29, this tube will accordingly become biased far `beyond itscut-olf point so as to be unresponsive to any pulses originating fromthe subject to be measured. Conversely, lack of voltage at point X,which is applied as bias to the cathode 58 of tube 21, will permit saidtube to remain in its slightly cut-olf state so as to be responsive tothe synchronizing pulses. Thus, in the condition described the apparatusis functioning in an indicating state and not in a count absorbing orreceiving state since the signal gate is disabled while the indicatinggate is operative. At every operation, the operate switch 53 must firstbe cled in order to extinguish tube 5 This does not in any way alter thebiased condition of tube 49. Thence, upon the opening of the switch, thescreen grid bias on tube 49 becomes zero, and the very next positivepulse from the ten cycle multivibrator i6 will re tube 49 which will inturn extinguish tube 50 through coupling capacitor 59. The resultantcurrent through resistor 56 will cause a blocking voltage to be appliedto the cathode 58 of tube 21, whereas the cathode 51 of tube 29 will berestored to substantially ground potential. Therefore, the oppositecondition Will be in effect wherein channel section A is inoperative dueto the blocking of tube 21, while channel section B will deliver pulsesto tube 33 for discharge of capacitor 3 At the next positive pulse fromthe multibrator I6, tube 50 will again be fired, thereby extinguishingtube 49 and tiring tube 5| through capacitor 6l). This action restoresthe screengrid bias to tube 49 and the circuit returns to its originalcondition. It will be observed that the control circuit comprising tubes49, 50 and 5| is put into operation by two successive pulses from ten'cycle multivibrator I6. Such source of operation is utilized when thedevice is to function as a frequency meter or similar apparatus,

since it will be evident that the interval be-V tween two successivepulses from multivibrator I6 is exactly one tenth of a second and thenumber of pulses from the source fx which are applied to tube 33 duringthis interval will be the `measure of the frequency 0f fx.

In other applications tubes 49, 50 and 5| may be energized through otherappropriate means.

Wheels 2|, 22 and 23 et seq. are provided with counting channels andgates similar to that described. Each such succeeding divider, however,is actuated by a preceding divider, rather than by input pulses directlyfrom the unknown frequency fx. Thus, pulses at the repetition rate, orfrequency of the original signal fx will be passed by the signal gatetube 29 to the phase inverter tube 44 and' thence to the capacitordischarging tube 33 during the one-tenth second interval that thechannel section B, as represented by the signal or carry gate anddivider is active. After every ten pulses applied to the multivibratortube '38 through its blocking capacitor. one pulse is sent to the nextdivider through a carry gate which duplicates the gate tube 29 of signalgate channel B. It will be noted that the point Y of the gate control isconnected to section B of each counting channel n lwhile point X isconnected to the section A of each such channel. Each succeeding carrygate of the cascaded dividers will be actuated by one pulse after tenhave been applied to the preceding counter. If desired the carry gatesof each succeeding channel section B may have an amplier 4l and a pulseshaper 4| for the purpose described above. For every ten pulses sent toone divider, one pulse goes to the succeeding divider and so on untilone-tenth of a second later when all the sections B will be blocked byvoltage from point Y, and the indicating or synchronizing pulses fromthe multivibrator I5 will be passed once more to every divider so astovrestore the synchronization of the rotating wheel cycle and the neontube dashing circuit. Prior to such restoration it will be recognizedthat the repetition rate of the light hashing circuit is varied duringone of its cycles according to the subject which is being counted. Thevariation, however, need not be confined to one cycle but may extendover many cycles. The variation of repetition rate is accomplished bythe acceleration of one cycle through the addition of signal pulsesalthough delay will be likewise eective.

In the indicating position, the corresponding channel sections in eachdivider will be operating identically, whereas in the condition whereincounts are absorbed or received, the rst divider is coupled to thesignal source, the frequency of which is measured for one-tenth of asecond, and the other dividers are coupled to a preceding divider toobtain Vthe number of carrys. At the termination of this period, alldividers are re-switched automatically to the indicating state and thewheels will show the number of accumulated counts or cycles which haveoccurred during this one-tenth second period. The result will beone-tenth oi the frequency of the incoming signal and will appear as anumber on the stroboscopically indicating wheels.

'Referring to Fig. 7, the counting or indicating wheels 2l, 2l, 22 and23 comprise annular members preferably, but not necessarily, of atransparent or translucent material such as glass or a synthetic resinsuch as Lucite, on which are inscribed the numerals 0 to 9 or any otherdesired symbols. Neon tube 24 is disposed within the annulus of wheelsand neon tubes 68, 65 and 'll arelsimilarly disposed in their wheels.Each neon tube is fed by the respective units, tens, hundreds, orthousands scale-of-ten divider, assuming that the apparatus comprisesfour such dividers.

The disposition of the neon tubes within the wheels oifers considerableoperating advantages inasmuch as the neon tubes are concealed andprotected against damage while the wheels may be conveniently mountedadjacent each other without creating mutual interference of the tubeflashes. If desired, doors or bailles may be proparatus may be requiredto be returned to a zero position of the counters preparatory to a newopvided between wheels to conne the effect of In Fig. 7, which is ablock diagram of a sub- .U

stantially complete system, the gate control is not illustrated asactuated by the 10 cycle source I6 since other adaptations may require.actuation thereof by other agencies, such as by the means of thesubject being measured. Pulse Shapers, and amplifiers for the carrygates of channels succeeding the first are not provalue.

eration. The re-setting of the counters to zero position involves thereturn of the random divider-cycle phases to a common condition withrespect to the positions of the rotating wheels. This may beaccomplished by discharging the capacitor 31 of each channel to theminimum point by reducing or cancelling the voltage of battery 34.Return to an indicating position may be automatically accomplished bythe gate control at precisely the correct moment after such re-setting.

Referring to Fig. 1, when the re-set switch 'H is closed, the X voltagefrom the control tube 49 will neutralize the battery 34 potential so asto permit the discharge of capacitor 31. The same eeet will be achievedin the following dividers through the point Z connection at re-setswitch 1|. It will be noted that the Z connection supplies the potentialof battery 34 to each multivibrator blocking capacitor and serves toreduce the effective bias on tubes 32 and 33 when the re-set switch isclosed. This reduction of bias permits these tubes to conduct so as todischarge the blocking capacitor to the desired The gate control meansdescribed will thus accomplish the re-setting function and will thenre-switch to the indicating position as required. During this re-settingoperation no transmission of pulses to the divider will be permitted byvirture of switch element 12 which is ganged to re-set switch 1I andwhich cuts off the pulse shaper 4I during a re-setting operation.

The apparatus herein described can function as an interval meter so asto measure the elapsed time between any two pulses. Thus, the device candetermine the time of opening and closing of contacts or the timebetween any two operations, or any condition wherein an interval can bedeiined by its start and finish. In addition the device may be arrangedto control a succeeding operation when a predetermined interval betweentwo pulses occurs.

Operation as an interval meter is essentially the reciprocal of afrequency meter. The two pulses, the interval between which is to bemeasured, are applied successively through coupling capaci` tors 54 or6l by means of an amplifier if desired to the gate control.Simultaneously a standard source of frequency is applied at point fx. Asan example, if the time interval between two incoming pulses were 0.156second apart, the first pulse would operate the gate control allowingthe standard frequency pulses to pass to the counter. The second pulsearriving 0.156 second later would stop the reception of the standardfrequency pulses and the device is automatically switched back toindicating. The standard frequency may be conveniently set at precisely1,000 cycles per second, whereby exactly 156 pulses will be counted bythe apparatus during the activation of section B by the interval startand finish and this number will be shown on the wheels. This will then,of course, indicate kthat the interval was .156 second.

1l.4 will be substantially that hereinabove described. During stand-byperiods, indicating is continuously eiected through the feeding oisynchronizing pulses simultaneously to all the dividers through leadwires 62, 63 and 84 as-well as to the rst divider. Thus, at the startingpoint the wheels will all have their zero numerals showing. Aspreviously described, each dividercounter is so connected during thereceiving or adding process that for each ten pulses received in theunits divider-counter, one is transmitted to the tens divider-counterand so on.

As an example if it were desired to add a column of figures wherein thenrst number is 278, these numbers may be depressed upon a suitable keyboard and the add button pushed.

`One method of accomplishing the foregoing'is to allow two pulses ofdischarge to be applied to the 100s divider-counter, seven such pulsesto the divider-counter and eight pulses to the unit divider. As analternative, predetermined, but different voltages may be applied to theseveral capacitors which would be equivalent to the aggregate value ofthe applied pulses since it can be understood that any method ofchanging the phase relationship of the blocking capacitor or lightflashing circuit, and the indicating wheel would effect the desiredresult. In the rst method oi addition described, however, the pulses maybe injected very rapidly in the succession 2-7-8, or in the reversesuccession 8-7-2, whereupon the apparatus may be automatically returnedto the indicating position wherein synchronizing pulses are sent to allthe dividers. 1t is not necessary to apply the numbers discretelybecause a very short and automatic time delay of an electrical naturecan be provided in the divider output to prevent interference betweencounts and carrys. An alternative could be the syncopation of theincoming pulses. for explanatory purposes, it will be assumed thatadditions occur as noted above.

It should be observed that the control circuit herein maintains eachdivider independent in the indicating position so that the applicationof synchronizing pulses merely maintains the cyclic synchronism of theneon tube circuits. and indicating wheels. If this were not done. theapplication of synchronizing pulses would cause each counter to carryover the succeeding counter in series of ten and would distort theresult of the computations. However, since in the indicating conditiontube 29 is disabled, no synchronizing pulses can be transmitted to thesucceedingcounters. It should be observed, however, that an arrangementis feasible wherein the counters are not thus independent and whereinthe appa- However,

ratus operates on a system of 9s, and conversion to 10s is effected byadditional pulses.

If the second number of the list was 36d, these numerals would bedepressed and the add" key lagain pushed. The indicating channel sectionwill thereupon be disabled once more while threeI pulses will be sent tothe hundreds divider, then, six pulses to the tens. It will be observedthat this will discharge the tens capacitor at the third pulse, therebyautomatically recharging the same to maximum and then dropping downthree more steps. The recharging of the tens divider capacitor transmitsa. pulse to the hundreds divider so that in all four pulses are appliedthereto by the addition of the second number. Similarly, when two of thefour pulses from the last numeral of the number 364 are fed to the unitsdivider, the capacitor will be recharged at the second pulse l2 so as toadd another pulse to the tens divider and will drop down two moredischarge decrements. It will be appreciated that this operation takesplace in a fraction ot a second. After the nal pulse has been sent, thedevice is automatiwhich obviously is the desired result.

Subtraction by the method herein outlined may be effected by using the9-complements system. Subtraction may also be eifected by rotating thewheels in the opposite direction so as to givethe 10-complements of eachnumber. Adding further numbers 'will appear as complements, which issubtraction. Means must be provided, however. to correct for impropercarrys as is well understood. In a 9-complements system, the operationsare similar to those previously described, but the depression of thesubtraction lever will cause the 9-complements to be added. As will beapparent to those skilled in the art, the first column of the subtractediigures must send a pulse to the last when "9 is exceeded.

I have shown a preferred embodiment of my invention, but it is obviousthat numerous changes and omissions may be made without departing fromits spirit. For example, while I have described the counter or scalingdevice as a. multivibrator wherein an indicating channel effects thedischarge of a blocking capacitor at a synchronous repetition rate. andwherein this repetition rate is momentarily varied during or after theapplication of the subject to be measured, it is apparent that ablocking oscillator having a similar capacitor in its grid circuit willserve the same function. In fact, any type of scaling or counting devicecan be used which will effect a variation of phase relationship betweenthe neon tube actuating circuit and the cyclical rotation of thecounting wheels. Thus, a glow tube counter, or conventionalmultivibrator scaling devices, may vary a capacitor charge in the neontube circuit which is flashed thereby. The principle of thus varying thephase relationship may be utilized in other types of indicating devicesemploying synchronism between two elements for indicating intelligenceupon one of them. In fact, since the readings actually indicate thephase, measurement of phase can be done directly.

I claim:

1. Measuring apparatus comprising a series of rotating indicia bearingwheels, light flashing members stroboscopically associated with saidwheels for rendering selected portions of said wheels apparent,electrical circuit means for actuating each said light flashing members,each of said electrical circuit means including an oscillator and acapacitor therein associated with its 13 light ilashing member,said-oscillator being operative by a predetermined change in the chargeof said capacitor for flashing its associated flashing member, means toeffect said predetermined change at a repetition rate synchronized withthe frequency of rotation of said wheels, means to vary the repetitionrate of at least one of said predeterminedA changes so as to change thephase relationship of said repetition rate and said wheel frequencyrotation whereby correspondingly var# ied portions of said wheels arerendered apparent, input means for introducing an electrical subject tobe measured, and means to effect said variation of repetition rate bysaid introduction.

2. Measuring apparatus comprising a series of rotating indicia bearingwheels, light flashing members stroboscopically associated with saidwheels for rendering selected portions of said wheels apparent,electrical circuit means for actuating each said light ilashing members,each of said electrical circuit means including an oscillator and acapacitor therein associated with its light hashing member, saidoscillator being operative by a predetermined change in the charge ofsaid capacitor for flashing its associated flash4 ing member, frequencycontrol means common to both said rotating wheels and said electricalcircuit means whereby said predetermined change is effected insynchronism with an integral number of revolutions of said wheels, inputmeans for varying said synchronisation during an interval of time, saidvariation being a function of an input subject to be measured, and meansto restore said synchronisation after said interval of time.

3. An electrical measuring instrument comprising a cascaded series offrequency dividers, a rotating, numbered wheel for each divider, a lightflashing member stroboscopically associated with each said wheel, meansto effect synchronisation of rotation of said wheels with the flashingof said members so as to normally render a specific number of eachrotating wheel visible, input means for introducing an electricalquantity to be measured into the first of said cascaded dividers, saidintroducing means being operative to momentarily vary saidsynchronisation whereby said synchronisation lis re-established so as torender a number visible on said wheel depending upon said variation ofsynchronisation, said first divider being adapted to transmit thedivided subject to the succeeding divider so as to vary its synchronismof wheel rotation and light ashing correspondingly, similartransmissions of further divisions of the subject being effectedthroughout the cascaded dividers.

4. Electrical measuring apparatus comprising a cascaded series ofrotating indicia bearing wheels, light flashing membersstroboscopicallyA associated with said wheels, electrical circuit meansfor actuating eachhof said light flashing members, a relaxationoscillator in each said electrical circuit, a capacitor arranged toblock said oscillator at each oscillation thereof and having nodischarge path in said oscillator' trical voltage being arranged to beeffectively added to the controlled discharge path of said capacitor soas to vary its time of discharge accordingly whereby each said lightflashing members is caused to flash at relative times cor- 14 respondingto the value of the voltage being measured.

5. Electrical measuring apparatus comprising an indicia bearing member,cyclical means for effecting periodic progression through the indicia ofsaid member, indicating means for selecting a portion of said member tobe indicated, a relaxation oscillator feeding said indicating meanswhereby each oscillation thereof operates said indicating means, meansto control the frequency of said relaxation oscillator so that saidindicating means is synchronized with the cyclical operation of saidmember, a reactance in said relaxation oscillator adapted to blockoscillations thereof when charged, said frequency controlling meansbeing operative to discharge said reactance at pre-determined,synchronized intervals, a count receiving channel, means to transformreceived counts into discharge decrements and apply said decrementsduring a period of time to said reactance additively with thedischarging function of said frequency controlling means whereby theresulting acceleration of discharge interrupts said synchronization,said frequency controlling means re-establishing said synchronizationafter said period of time of said application of discharge decrements.

6. Measuring apparatus comprising a cascaded series of rotatablenumbered wheels, `light flashing tubes stroboscopically associated withsaid wheels, means for effecting rotation of said wheels and theflashing of said tubes in synchronism whereby specific numbers of saidwheels are rendered apparent during said rotation, an electrical circuitfor actuating each of said tubes, a relaxation oscillator in each ofsaid circuits, a capacitor in each said oscillator and adapted to becharged so as to block said oscillator at each oscillation thereof,means to discharge said capacitor at regularly spaced intervals, saiddischarge being arranged to ash the tube associated with its circuitwhereby said regularly spaced discharge makes a single number apparenton the fwheel associated with said tube, and a count receiving circuitconnected into said electrical circuit and operative to apply dischargedecrement voltages to said capacitor in accordance with the amplitude ofan electrical voltage to be measured whereby the time of dischargethereof with respect to the rotating wheel is modified, each of saidelectrical circuits being cascaded to apply counts to a succeedingcircuit and being operative to electrically divide said applied countsand to apply the divided counts to each succeeding circuit until thelast circuit, said divided counts applied to each of said succeedingcircuits serving to modify the time of discharge of its blockingcapacitor.

'7. Measuring apparatus according to claim 6 including control means forselectively rendering operative either said regularly spaced intervaldischarging means or said count receiving circuit application ofdischarge decrements whereby the operation of said spaced intervaldischarging means may be interrupted to allow the application of saiddischarge decrements and may be automatically resumed after an intervalof time determined by the operation of said control means.

8. Measuring apparatus according to claim 6 including control means forselectively rendering operative either said regularly spaced intervaldischarging means or said count receiving circuit application ofdischarge decrements, means to apply said discharge decrements in theform of discrete pulses and means t apply Operating impulses to saidcontrol means, said operating impulses being spaced apart by apre-determined interval of time whereby the number oi dischargedecrements discretely applied to said capacitor during said interval isa measure of the frequency of saiddiscrete discharge decrements.

9. Measuring apparatus comprising a cascaded series of rotatablenumbered wheels, light flashing tubes stroboscopically associated withsaid wheels, means for effecting rotation of said wheels and theflashing of said tubes in synchronism whereby specific numbers of saidwheels are rendered apparent during said rotation, an electrical circuitfor actuating each of said tubes, a relaxation oscillator in each ofsaid circuits, a capacitor in each said oscillator and arranged to becharged so as to block said oscillator at each oscillation thereof,means to discharge said capacitor at regularly spaced intervals, saiddischarge being arranged to flash the tube associated with its circuitwhereby said regularly spaced discharge makes a single number apparenton the wheel associated with said associated gas tube, and a countreceiving circuit connected into said electrical circuit and adapted toapply discharge decrement voltages to said capacitor of a knownfrequency whereby the time of discharge thereof with respectto therotating wheel is modified as to change the previous phase relationshipof the synchronized wheel rotation and tube flashing and make acorresponding number of the wheel apparent by the flashing tube, controlmeansv for selectively rendering operative either said regularly spacedinterval discharging means or said known frequency discharge decrementsand means to apply two operating impulses to said control means, saidoperating impulses being spaced apart a period of time the duration ofwhich is to be measured whereby said rst operating impulse permits theapplication of said known frequency discharge decrements and said second4impulse stops said application so that the number of known frequencydischarge decrements applied during said two impulses is a measure ofthe time of said interval.

10. Electrical measuring apparatus comprising a cascaded series ofrotating indicia bearing wheels, light flashing members stroboscopicallyassociated with said wheels, electrical circuit means for flashing saidlight members so as to render a specific portion of each said wheelsvisible, a one hundred cycle frequency pulse source, a first electricalpath for each light flashing member, said first electrical path beingarranged to receive said pulses, each of said electrical circuit meansbeing adapted to divide said pulses in a scale of ten ratio and to flashsaid light members thereby, means to rotate said wheels one revolutionfor each resulting divided pulse so as to maintain synchronism betweensaid rotating wheels and said flashing of said light members, and asecond electrical path for supplying pulses to said electrical circuitmeans to be similarly divided thereby and to be added to said onehundred cycle divided pulses, control means for selectively renderingoperative either said first electrical path or said second electricalpath, each of said electrical circuit means being mutually independentwhen said first electrical path is operative so as to permit visibilityof numbers recurring in synchronism with the flashing of said lightmembers,/sa^id electrical circuit means being mutually interconnectedwhen said second electrical path is operative, said interconnection 16being adapted to subdivide the divided output of each electrical circuitmeans until the last thereof whereby scale-of-ten dividers are providedin cascaded relationship. v 5 11. Measuring apparatus according to claim10 including a relaxation oscillator in each electrical circuit, ablocking capacitor in each relaxation oscillator to be charged upon eachoscillation thereof, said rst electrical path being adapted to supplystepped discharge decrements in series of ten, said second electricalpath being adapted to supply stepped discharge decrements according to avoltage to be measured, all said 'discharge decrements having the samecapacitor discharging value.

12. Measuring apparatus according to claim 11 wherein said control meanscomprises a trigger circuit having two stable operating conditions,means to supply two pulses thereto for maintaining said trigger circuitin one of its conditions during the interval between said two pulses,said trigger circuit being adapted to produce disabling bias voltagesfor either of said electrical paths depending upon its condition ofstability as determined by said two pulses.

13. Measuring apparatus comprising a series of rotating indicia bearingwheels, light flashing members stroboscopically associated with vsaidwheels for rendering selected portions of said wheels apparent,electrical circuit means for actuatingweach said light flashing members,each of said electrical circuit means including a capacitor associatedwith its light flashing member, means responsive to a predeterminedchange in the charge of said capacitor for flashing its associatedflashing member, frequency control means common to both said rotatingwheels and said electrical circuit means whereby said predeterminedchange is continuously effected in synchronism with an integral numberof revolutions of said wheels, voltage receiving and applying means foradding charges to said capacitor, said voltage receiving means beingarranged to add said charges during a period of interrupg tion of theapplication of said control means to said electrical circuit means, saidvoltage receiving means being adapted to leave said capacitor in a stateof charge depending upon the voltage to be measured, whereby therestoration of said sa control Imeans to said electrical circuit meansafter said interruption produces the first predetermined change of thecapacitor thereof at an earlier time depending upon the charge leftthereon on said capacitor, each of said electrical 55 circuit meansuntil the last thereof feeding a succeeding electrical circuit means ina cascaded divider relationship so as to similarly accelerate the firstpredetermined change in the charge of their capacitors after saidrestoration.

14. Measuring apparatus according to claim 13 including a gate controltrigger circuit for selectively rendering operative either said controlmeans or said voltage receiving means by producing disabling voltagesselectively applied G5 thereto, said disabling voltages beingadditionally operative to reduce all of said capacitors to a commonstate of charge when an operation is concluded.

Y 15. Electrical measuring apparatus comprising 70 a cascaded series ofrotating indicia bearing wheels, light flashing members stroboscopicallyassociated with said wheels, electrical circuit means for actuating eachof said light flashing members cyclically so as to render specific porutions of said wheels visible, a relaxation oscillator i7 in each saidelectrical circuit means, a capacitor in each oscillator and beingoperative to block said oscillator at each oscillation thereof andhaving no discharge path in said oscillator whereby the normal frequencyof said oscillator is substantially zero, a capacitor discharge circuithaving a frequency of operation synchronized with the rotation oi saidwheels and connected to said capacitor so as to discharge said capacitorat each cycle or the capacitor discharge circuit whereby said oscillatoris provided with said rotating wheel frequency so as to render aparticular portion of each wheel visible, input means for receiving anelectrical voltage to bemeasured, said input means being operative toapply said electrical voltage to said capacitor so as to accelerate thedischarge thereof to a degree depending upon the amplitude oi'said-voltage be,

18 connected to a succeeding electrical circuit-means so as to feed animpulse thereto when caused to oscillate by the discharge of itscapacitor, said impulses serving to accelerate the discharge of thecapacitor in the electrical circuit means fed thereby.

CARL A. VOSSBERG.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 1,933,650 Bascom Nov. 7, 19332,184,355 Libman Dec. 26, 1939 2,278,993 Johnson Apr. '1, 1942 2,346,251Bryce Apr. 11, 1944 FOREIGN PATENTS Number Country Date 542,927 GermanyFeb. 3. 1942

